Polishing platens and polishing platen manufacturing methods

ABSTRACT

Embodiments of the present disclosure generally relate to methods of manufacturing polishing platens for use on a chemical mechanical polishing (CMP) system and polishing platens formed therefrom. A method of manufacturing a polishing includes positioning a polishing platen on a support of a manufacturing system. The manufacturing system includes the support and a cutting tool facing there towards. Here, the polishing platen includes a cylindrical metal body having a polymer layer disposed on a surface thereof and the polymer layer has a thickness of about 100 μm or more. The method further includes removing at least a portion of the polymer layer using the cutting tool to form a polishing pad-mounting surface. Beneficially, the method may be used to form a pad-mounting surface having a desired flatness or shape, such as a concave or convex shape.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application Ser.No. 62/855,894, filed on May 31, 2019, which is herein incorporated byreference in its entirety.

BACKGROUND Field

Embodiments described herein generally relate to polishing platens to beused on a chemical mechanical polishing (CMP) system and polishingplaten manufacturing methods related thereto.

Description of the Related Art

Chemical mechanical polishing (CMP) is commonly used in themanufacturing of high-density integrated circuits to planarize or polisha layer of material deposited on a substrate. In a typical CMP process,a substrate is retained in a carrier head that presses the backside ofthe substrate towards a rotating polishing pad in the presence of apolishing slurry. Material is removed across the material layer surfaceof the substrate in contact with the polishing pad through a combinationof chemical and mechanical activity which is provided by the polishingslurry and a relative motion of the substrate and the polishing pad.

Typically, the polishing pad is disposed on a disk-shaped polishingplaten having a surface which has been formed to have a desiredflatness. The polishing pad is secured to the surface of the platenusing a pressure sensitive adhesive layer interposed there between.Generally, polishing pads have a limited useful lifetime which thusnecessitates that the polishing pad be replaced on a regular basis toprevent degradation of CMP substrate processing results. Replacing thepolishing pad generally comprises manually pulling the polishing padfrom the surface of the polishing platen with enough force to overcomethe tenacity of the adhesive interposed there between. A typical forcerequired to remove a used polishing pad from the surface of a polishingplaten can be substantial which may lead to personal injury, damage tothe polishing system including damage to the polishing platen, or both.

Treating the surface of the polishing platen, such as by applying acoating of low-adhesion-material thereto, e.g., a “non-stick” polymercoating, can desirable reduce the force required to remove a usedpolishing pad therefrom. The treated surface may also desirably preventcorrosion of the polishing platen due to the exposure to the CMPpolishing chemistry during normal processing. Unfortunately, therelatively high temperature processes, which may be used to apply a lowadhesion material, can undesirably deform, e.g., warp, the disk-shapedpolishing platen thus reducing the surface flatness thereof. Also,typical conventional polymer coating thicknesses are large enough tosignificantly deform under the compressive load applied to the polishingpad and polishing platen by the substrate and portions of the polishinghead (e.g., substrate holder) during a CMP process. The amount of localand overall deformation of a polishing platen is generally notconsistent from coated platen to coated platen, which contributes toinconsistent substrate polishing results between polishing platens of amulti-platen polishing system and/or between single platen andmulti-platen polishing systems.

Accordingly, there is a need in the art for polishing platenmanufacturing methods, and polishing platens formed therefrom, thatsolve the problems described above.

SUMMARY

Embodiments of the present disclosure generally relate to methods ofmanufacturing polishing platens for use on a chemical mechanicalpolishing (CMP) system, polishing platens formed therefrom, andpolishing method using the polishing platens.

In one embodiment, a method of manufacturing a polishing platen isprovided. The method includes positioning a polishing platen on asupport of a manufacturing system. The manufacturing system includes thesupport and a cutting tool facing there towards. Here, the polishingplaten includes a cylindrical metal body having a polymer layer disposedon a surface thereof and the polymer layer has a thickness of about 100μm or more. The method further includes removing at least a portion ofthe polymer layer using the cutting tool to form a polishingpad-mounting surface. Beneficially, the method may be used to form apad-mounting surface having a desired flatness or shape, such as aconcave or convex shape.

In another embodiment, a polishing platen is provided. The polishingplaten features a cylindrical metal body and a polymer coating layerdisposed on the metal body to form a circular pad-mounting surface. Thepad-mounting surface has a first surface height at a first radius and asecond surface height at a second radius. The second radius is disposedradially inward of the first radius. The first and second surfaceheights are measured as distances from a reference plane that isparallel the pad-mounting surface at the first radius. A differencebetween the first and second surface heights is about 25 μm or more. Insome embodiments, the first and second surface heights are averaged froma plurality of distance measurements taken at a corresponding pluralityof equidistant locations along the respective radiuses.

In another embodiment, a polishing platen features a cylindrical metalbody and a polymer coating layer disposed on the metal body to form apad-mounting surface where a thickness of the polymer coating layerchanges from a first radius of the pad-mounting surface to a secondradius disposed radially inward from the first radius. In someembodiments, the thickness at the second radius is averaged from aplurality of thickness measurements taken at a corresponding pluralityof equidistant locations along the second radius and a differencebetween the thickness at the first radius and the second radius is about25 μm or more.

In another embodiment, a method of polishing a substrate is provided.The method includes urging a substrate against a surface of a polishingpad in a presence of a polishing fluid. Here, the polishing pad isdisposed on a pad-mounting surface of a polishing platen. The polishingplaten includes a cylindrical metal body and coating layer disposed on asurface of the metal body to form the polishing pad-mounting surface.The mean thickness of the coating layer across the pad-mounting surfaceis less than about 250 μm and a variation in the thickness of thecoating layer across a diameter of the pad-mounting surface varies byabout 25 μm or more. The pad-mounting surface may have a flatness ofabout 25 μm or less or may have a concave or convex shape.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above-recited features of the presentdisclosure can be understood in detail, a more particular description ofthe disclosure, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this disclosure and are therefore not to beconsidered limiting of its scope, for the disclosure may admit to otherequally effective embodiments.

FIG. 1A is a schematic side view of an exemplary polishing system,according to one embodiment, which is configured to use a polishingplaten formed according to the methods set forth herein.

FIG. 1B is a schematic cross sectional view of the platen assembly ofFIG. 1A, according to one embodiment.

FIG. 1C is a close up view of a portion of FIG. 1B.

FIG. 2 is a diagram illustrating a method of manufacturing a polishingplaten, according to one embodiment.

FIG. 3 is a schematic side view of a manufacturing system that may beused to practice the methods set forth in FIG. 2, according to oneembodiment.

FIG. 4 is a graph depicting a surface profile of a portion of apolishing platen formed according to embodiments described herein.

FIGS. 5A-5H are schematic sectional views illustrating various polishingplaten surface profiles that may be formed according to embodimentsdescribed herein.

FIG. 6 is a diagram illustrating a method of polishing a substrate usinga polishing platen formed according to embodiments described herein.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements disclosed in oneembodiment may be beneficially utilized on other embodiments withoutspecific recitation.

DETAILED DESCRIPTION

Embodiments of the present disclosure generally relate to methods ofmanufacturing polishing platens for use on a chemical mechanicalpolishing (CMP) system and polishing platens formed therefrom. Thepolishing platens formed according to embodiments herein generallyfeature a structural component, such as a cylindrical platen body formedof metal, and a low-adhesion-material layer disposed on a surface of theplaten body to provide a polishing pad-mounting surface. Thelow-adhesion-material layer desirably reduces the amount of forcerequired to remove a polishing pad from the polishing pad-mountingsurface once the polishing pad has reached the end of its usefullifetime and further protects the metal of the platen body frompolishing fluid caused corrosion.

Often, the processes required to form and bond the low-adhesion-materialto the surfaces of the platen body require heating and maintaining theplaten body at temperatures in excess of 300° C., for example up to 350°C. or more, during the material deposition process. Typically, the hightemperature process used to form the low-adhesion-material layer causesthe cylindrical platen body to become deformed, which undesirablyreduces the flatness of the pad-mounting surface thereof. For example,in some embodiments the pad-mounting surface of the platen body ismachined to have a flatness deviation from a least squares referenceplane of about 25 μm or less before a coating layer of thelow-adhesion-material is formed thereon. After the coating layer isformed on the platen body, the pad-mounting surface may suffer from alack of flatness. For example, the pad-mounting surface may have adeviation from the reference plane by about 25 μm or more, such asbetween about 25 μm and about 150 μm, even though thelow-adhesion-material coating layer may have a thickness uniformitystandard deviation about 3 μm or less.

Generally, the distortions in the shape of the polishing platenfollowing the low-adhesion-material coating process are unpredictable.Thus, the low-adhesion material coating process may result differentsurface profiles for different polishing platens formed using the samematerial coating process. For example, two different disk-shapedpolishing platens formed using generally the same low-adhesion-materialcoating process may each have a different resulting surface shapecomprising such as different hyperbolic paraboloid surface shapes, ordifferent random undulating surface shapes, in various degrees ofdeviation from a least squares reference plane thereof. Unfortunately,the variations in surface shape of different polishing platens formedusing the same surface coating methods undesirably result in non-uniformsubstrate processing results from polishing platen to polishing platenwithin a multi-platen CMP system and/or across a plurality of singleplaten CMP systems or multi-platen CMP systems. Therefore, embodimentsherein provide methods for controlling the flatness and/or surface shapeof a polishing platen during the manufacturing thereof and polishingplatens formed using the methods. In one embodiment, a method includesforming a relatively thick low-adhesion-material layer on thedisk-shaped platen body before removing portions of the material layertherefrom to provide a polishing platen having a desired surfaceflatness and/or surface shape.

FIG. 1A is a schematic side view of an exemplary polishing system 100,which includes a platen assembly 102, formed using the methods describedherein. FIG. 1B is a schematic cross sectional view of the platenassembly 102 of FIG. 1A. Herein, the platen assembly 102 includes alower platen 104 and a polishing platen 106 disposed on and coupled tothe lower platen 104. FIG. 1C is a close up view of a portion of thepolishing platen 106 shown in FIG. 1B.

The exemplary polishing system 100 includes the platen assembly 102having a polishing pad 110 mounted thereon, a substrate carrier 108disposed above the polishing pad 110 and facing there towards. Theplaten assembly 102 is rotatable about an axis A, the substrate carrier108 is rotatable about an axis B and is configured to sweep back andforth from an inner diameter to an outer diameter of the platen assemblyto, in part, reduce uneven wear of the surface of the polishing pad 110.The polishing system 100 further includes a fluid delivery arm 118positioned above the polishing pad 110 which may be used to deliverpolishing fluids thereto and a pad conditioning assembly 120 disposedabove the polishing pad 110 and facing there towards.

In a typical CMP process, the rotating and/or sweeping substrate carrier108 exerts a downforce against a substrate 112 (shown in phantom)disposed therein to urge a material surface of the substrate 112 againstthe polishing pad 110 as the polishing pad 110 rotates there beneath.The substrate 112 is urged against the polishing pad 110 in the presenceof the one or more polishing fluids delivered by the fluid delivery arm118. A typical polishing fluid comprises a slurry formed of an aqueoussolution having abrasive particles suspended therein. Often, thepolishing fluid contains a pH adjuster and other chemically activecomponents, such as an oxidizing agent, to enable chemical mechanicalpolishing of the material surface of the substrate 112.

The pad conditioning assembly 120 is used to urge a fixed abrasiveconditioning disk 122 against the surface of the polishing pad 110rotating there beneath before, after, or during polishing of thesubstrate 112. Conditioning the polishing pad 110 with the conditioningdisk 122 maintains the polishing pad 110 in a desired condition byabrading, rejuvenating, and removing polish byproducts and other debrisfrom, the polishing surface of the polishing pad 110.

In some embodiments, the polishing system 100 further includes aprocessing endpoint detection system 125, which is used to monitor thethickness of a material layer or to monitor the removal of a materiallayer from a field surface of the substrate 112 during the polishingprocess. The processing endpoint detection system 125 includes one ormore sensors, such as an eddy current sensor or an optical sensor, whichare housed in a cavity 130 (FIG. 1B) of the platen assembly 102.

The platen assembly 102 (FIGS. 1A-1C) includes a lower platen 104 and apolishing platen 106 disposed on the lower platen 104 and coupledthereto. Here, the lower platen 104 has a top down circular shape, anannular polishing platen mounting surface 126, and one or more recessedsurfaces 146 disposed radially inward from the polishing platen mountingsurface 126, which together with the polishing platen 106, defines thecavity 130. The polishing platen 106 is disposed on the polishing platenmounting surface 126 and is secured thereto using a plurality offasteners 138. Here, the plurality of fasteners are disposed throughcorresponding openings formed in an annular flange shaped portion 140 ofthe lower platen 104.

The polishing platen 106 is formed of a cylindrical disk-shaped platenbody 142 and includes a low-adhesion-material coating layer 144 formedon one or more surfaces of the platen body 142. For example, here theplaten body 142 has a first surface (the platen body surface 132), asecond surface 134 that is opposite of the platen body surface 132 andsubstantially parallel thereto, and a radially outward facingcircumferential surface 136 connecting the platen body surface 132 tothe second surface 134. The material coating layer 144 is formed on theplaten body surface 132 to provide a low-adhesion pad-mounting surface148 and is further formed on the circumferential surface 136 to protectthe platen body 142 from polishing fluid caused corrosion. In someembodiments, the polishing platen 106 includes an aperture 124, such asa window, formed there through. The endpoint detection system 125 may beused to monitor the substrate polishing processed using one or moresensors positioned proximate to the aperture 124.

The polishing platen assembly 102, and thus the polishing platen 106,may be suitably sized for any desired polishing system. For example,here the sized for a multi-platen polishing system configured to polisha 300 mm diameter substrates and has diameter of more than about 300 mm,such as between about 500 mm and about 1000 mm, or more than about 500mm. Generally, the polishing platen 106 is relatively thin, where athickness thereof is between about 20 mm and about 150 mm, or about 100mm or less, such as about 80 mm or less, about 60 mm or less, or about40 mm of less. Appropriate adjustments may be made to the size of thepolishing platen 106 for polishing systems configured to polishdifferent sized substrates, e.g., 200 mm diameter or 450 mm diametersubstrates, or for a polishing platen 106 sized for concurrent polishingof multiple substrates. In some embodiments, a ratio of a diameter to athickness of the polishing platen 106 is about 3:1 or more, about 5:1 ormore, about 10:1 or more, about 15:1 or more, about 20:1 or more, about25:1 or more, about 30:1 or more, about 40:1 or more, or for example,about 50:1 or more.

The platen body 142 is formed of a suitably rigid, light weight, andpolishing fluid corrosion resistant material, such as aluminum, analuminum alloy (e.g., 6061 Aluminum), or stainless steel. The coatinglayer 144 typically comprises a polymer material formed of one or morefluorine-containing polymer precursors or melt-processablefluoropolymers, such as perfluoroalkoxy polymer (PFA), fluorinatedethylene-propylene (FEP), monofluoroalkyl polymer (MFA),olytetrafluoroethylene (PTFE), tetrafluoroethylene-ethylene (ETFE),polychlorotrifluoroethylene (PCTFE), polyvinylidene fluoride (PVF2), andcopolymers formed from a combination of more than one of the polymerprecursors thereof. In some embodiments, the coating layer 144 is formedof a perfluoroalkoxy alkane (PFA), e.g., a copolymer oftetrafluoroethylene and one or more perfluoroethers (C₂F₃OR^(f), whereR^(f) is a perfluorinated group such as trifluoromethyl (CF₃)). In otherembodiment, the material coating layer 144 may be formed ofpolyphenylene sulfide (PPS), polyetheretherketone (PEEK), thermoplasticpolyimide (TPI), polyetherimide (PEI), polyamideimide (PAI), liquidcrystal polymers (LCP), combinations thereof, and/or in combination withone or more fluorine-containing polymer.

Herein, the material coating layer 144 is formed by forming a firstpolymer layer 150 (shown in phantom in FIG. 1C) on the surface of theplaten body 142 before removing portions of the first polymer layer 150to provide a pad-mounting surface 148 having a desired flatness orshape. Examples of suitable methods which may be used to form the firstpolymer layer 150 include dipping, spraying, e.g., a plasma spraycoating method or a thermal spray coating method, and electrostaticdeposition of a liquid or powder polymer precursor. In some embodiments,forming the first polymer layer 150 includes heating the platen body 142and the polymer or polymer precursor material deposited thereon to atemperature of more than about 250° C., such as more than about 300° C.,or more than about 350° C.

In some embodiments, the first polymer layer 150 is formed to have athickness t_(i) of about 100 μm, such as about 120 μm or more, about 140μm or more, about 160 μm or more, about 180 μm or more, for exampleabout 200 μm or more. Herein, the thickness t_(i) of the first polymerlayer 150 is substantially uniform across a platen body surface 132disposed there beneath. For example, in one embodiment, a standarddeviation a of a plurality of measurements of the thickness t_(i) of thefirst polymer layer 150 taken in uniform increments across a diameter ofthe platen body surface 132 is less than about 10 μm, such as less thanabout 9 μm, less than about 8 μm, less than about 7 μm, less than about6 μm, or for example, less that about 5 μm.

In some embodiments, the platen body surface 132, and thus the surfaceof the first polymer layer 150, suffer from a lack of flatness where atleast some portions of the surface of the first polymer layer 150deviate from a reference plane, such as a least squares reference plane,by about 25 μm or more, such as by about 50 μm or more, about 75 μm ormore, about 100 μm or more, about 150 μm or more, about 175 μm or more,about 200 μm or more, or, for example, between about 25 μm and about 200μm. Thus, in some embodiments, after the first polymer layer 150 isformed on the platen body 142, at least portions thereof are removed toform a second polymer layer, herein the material coating layer 144.Removing at least portions of the first polymer layer 150 forms apolishing platen 106 with a pad-mounting surface 148 having a desiredflatness or surface shape. A method removing at least a portion of thefirst polymer layer 150 to form a polishing platen 106 having a desiredflatness or surface shape is set forth in FIG. 2.

FIG. 2 is a diagram illustrating a method 200 of forming a desired shapein a pad-mounting surface of a polishing platen, according to oneembodiment. FIG. 3A illustrates a manufacturing system 300, according toone embodiments, which may be used to practice the method 200.

At activity 202, the method 200 includes positioning a polishing platen310 on a manufacturing support of a manufacturing system 300 used forshaping metals or other rigid material, such as a lathe or a millingmachine. Here, the manufacturing system 300 is a vertical turning lathewhich features a support spindle 302 which is rotatable about a spindleaxis 304, a mounting fixture 306 secured to the support spindle 302, anda cutting tool 308 disposed above the support spindle 302 and facingthere towards. Here, the mounting fixture 306 is substantially similaror the same as the lower platen 104 describe above in FIGS. 1A-1B. Thepolishing platen 310 is secured to the mounting fixture 306 using aplurality of fasteners 312 which are adjustable in the Z-direction topull or push the outer radius of the mounting fixture 306, and thus thepolishing platen 310, towards or away from the support spindle 302. Insome embodiments, the manufacturing system 300 further includes asurface profiler 314, such as a dial gauge, coupled to the cutting tool308 which may be used to measure the flatness of the polishing platen310 before, during, and after surface profile modification thereof.

At activity 204, the method 200 includes removing at least a portion ofthe first polymer layer 150 using the cutting tool 308 to provide apad-mounting surface 148 having a desired flatness or surface shape.Here, removing at least a portion of the coating layer includes movingone or both of the cutting tool 308 and the polishing platen 310 whilemaintaining a desired distance in the Z-direction there between tocontrol the depth of material removal. Here, the cutting tool 308 isconfigured to move radially inward from an outer radius of the polishingplaten 310 to at least the center thereof (or vice versa) while thepolishing platen 310 rotates there beneath. Thus, the relative motion ofthe polishing platen 310 and the cutting tool 308 results in a spiralshaped cutting path from the surface of the polishing platen 310,wherein the spiral pattern extends from a central region (e.g., centralaxis) of the polishing platen 310 to the outside edge of the polishingplaten 310. In other embodiments, such as in embodiments where themachine tool is a mill comprising an X-Y translational stage therelative motion of a milling cutting tool and the polishing platen 310may result in a raster shaped cutting path from the surface of thepolishing platen.

The method 200 may be used to modify the profile of a pad-mountingsurface 148 of the polishing platen 106 into any desirable shape, suchas a substantially planer, convex, or concave shape.

In some embodiments, the method 200 may be used to form a substantiallyplaner pad-mounting surface 148 in which a standard deviation of aplurality of measurements taken at regular intervals there across from aleast squares reference plane of the pad-mounting surface 148 is about25 μm or less. In those embodiments, removing portions of the firstpolymer layer 150 to provide the substantially planar pad-mountingsurface 148 results in variations in the thickness of the coating layer144 across a diameter of the polishing platen 106. For example, theplaten body surface 132 of the portion of the polishing platen 106 shownin FIG. 1C has a concave surface profile, the first polymer layer 150disposed on the platen body surface 132 has a uniform thickness t_(i),and the concave surface profile, and the surface of the material coatinglayer 144 has a substantially planar profile. In FIG. 1C, removing atleast a portion of the concave surface of first polymer layer 150 toprovide the substantially planer surface of material coating layer 144results in a material coating layer 144 having a non-uniform thickness(t₂−t₁) across at least the portion shown. Thus, in some embodiments avariation in the thickness of the material coating layer 144 across adiameter of the pad-mounting surface 148 is not null. For example, insome embodiments, a variation in the thickness of the coating layer 144across the pad-mounting surface 148 is about 10 μm or more, such asabout 20 μm or more, about 30 μm or more, about 40 μm or more, or about50 μm or more. Typically, the coating layer 144 has a minimum thicknessof about 25 μm or more, such as about 50 μm or more and a maximumthickness of about 250 μm or less.

In some embodiments, the method 200 may be used to form a pad-mountingsurface 148 having a concave shape or a convex shape, such as thesubstantially concave shape shown in FIG. 4.

In some embodiments, the method 200 further includes forming a desirableshape in the platen body surface 132 before forming the first polymerlayer 150 thereon. For example, in some embodiments, the method 200 mayinclude machining the platen body 142 to form a concave shape or aconvex shape in the platen body surface 132, such as illustrated inFIGS. 5D-5E, before forming the first polymer layer 150 there over.

FIG. 4 is a graph 400 depicting a profile of a pad-mounting surface of apolishing platen formed according to the method 200. The polishingplaten in FIG. 4 is sized for use in a multi-platen system where eachplaten is sized to polish a single 300 mm diameter substrate. Thepolishing platen has a radius of about 380 mm and is formed to have apolishing pad-mounting surface 405 comprising a substantially concaveshape where a difference in a height between a center of thepad-mounting surface 405 and an edge of the pad-mounting surface isabout 76 μm. Here, measurements taken along a radius of the pad-mountingsurface 405 deviate from a circular convex curve 410 having a radius R₁by about 5 μm or less. Beneficially, the method 200 herein may be usedto form pad-mounting surfaces having a substantially concave shape or asubstantially convex shape where a plurality of measurements taken atequal intervals across a radius of the pad-mounting surface have a meandeviation from a radius of curvature R1 for the desired shape by about20 μm or less, such as about 15 μm or less, about 10 μm or less, orabout 5 μm or less.

FIG. 5A is a schematic sectional view of a polishing platen 500 a whichincludes a platen body 502 a having a first polymer layer 504 a formedthereon. The platen body 502 a and the first polymer layer 504 a may bethe same or substantially similar to the platen body 142 and firstpolymer layer 504 a described above in FIGS. 1A-1C. For example, in FIG.5A the first polymer layer 504 a is deposited to a substantially uniformthickness t_(i) having the same uniformity and thickness t_(i) of thefirst polymer layer 150 described above in FIG. 1C. As shown, a surface506 of the platen body 502 a is substantially planar, i.e., flat, andthus surface 508 a of the polymer layer 504 a is also substantially fat.However, it is contemplated that in embodiments herein the surface ofthe platen body 502 a may comprise any one or combination of shapes,such as a hyperbolic paraboloid surface shape (sometimes referred to asaddle shape or a potato chip shape), or a random undulating surfaceshape. In the examples of a hyperbolic parabolic surface shape, or arandom undulating surface shape, a cross sectional view of the platenbody 502 a may have both concave and convex surface profiles (dependingon where the sectional lines are taken).

FIGS. 5B-5C are schematic sectional views of respective polishingplatens 500 b-c formed by removing at least a portion of the firstpolymer layer 504 a using the method 200. In FIG. 5B, the portion of thefirst polymer layer 504 a (shown in phantom) is removed to form acoating layer 504 b which provides a pad-mounting surface 508 b. Thepad-mounting surface 508 b is formed to have a substantially radiallysymmetric convex shape with a radius of curvature R₁ across a diameterof the polishing platen 500 b. In this embodiment, a height h asmeasured from the center C of the concave pad mounting surface 508 b toa location disposed proximate to the circumferential edge E of thepad-mounting surface 508 b is about 10 μm or more, such as about 20 μmor more, about 30 μm or more, about 40 μm or more, about 50 μm or more,about 60 μm or more, or for example about 70 μm or more. Here, thecenter C of the pad-mounting surface 508 b is coplanar with a referenceplane P. The pad-mounting surface 508 b is spaced apart from thereference plane P by a distance Z₂ about a radius proximate to thecircumferential edge of the pad-mounting surface 508 b. Here, thedistance Z₂ is substantially the same about the radius so that thereference plane P is parallel to the pad-mounting surface 508 b aboutthe radius proximate to the circumferential edge. In this embodiment,the distance Z₂ is the same as the height h.

Here, a thickness t_(c) of the coating layer 504 b at the center C ofthe polishing platen 502 b, or at a first radius proximate thereto, ismore than the thickness t_(e) of the coating layer 504 b at, orproximate to, a circumferential edge E of the polishing platen 502 b. Insome embodiments, a difference between the thickness t_(c) and thethickness t_(e) is about 10 μm or more, such as about 20 μm or more,about 30 μm or more, about 40 μm or more, about 50 μm or more, about 60μm or more, about 70 μm or more, about 80 μm or more, or about 90 μm ormore.

In FIG. 5C, the portion of the first polymer layer 504 a (shown inphantom) is removed to form a coating layer 504 c which provides apad-mounting surface 508 c having substantially radially symmetricconcave shape with a radius of curvature R₁ across a diameter of thepolishing platen 500 c. Here, a difference in height h of thepad-mounting surface 508 c measured from the center C to acircumferential edge E of the polishing platen 500 c is about 10 μm ormore, such as about 20 μm or more, about 30 μm or more, about 40 μm ormore, about 50 μm or more, about 60 μm or more, or for example about 70μm or more. Here, a thickness t_(c) of the coating layer 504 b at thecenter C of the polishing platen 502 b is less than the thickness t_(e)of the coating layer 504 b at, or proximate to, a circumferential edge Eof the polishing platen 502 b. In some embodiments, a difference betweenthe thickness t_(c) and the thickness t_(e) is about 10 μm or more, suchas about 20 μm or more, about 30 μm or more, about 40 μm or more, about50 μm or more, about 60 μm or more, about 70 μm or more, about 80 μm ormore, or about 90 μm or more. In this embodiment, the center C of thepad-mounting surface 508 c is spaced apart from the plane P by adistance Z₁, which is the same as the height h. The pad-mounting surface508 c is coplanar with the plane P at a radius proximate to thecircumferential edge E of the pad-mounting surface 508 c.

Typically, R₁ may be determined from the equation R₁ ²=(R₁−h)²+r² wherer is the radius of the polishing platen. In one example, the radius ofcurvature R₁ for a 381 mm platen (radius) having either a substantiallyconcave or convex pad-mounting surface 508 b,c and a height h of about76 μm is about 952 m.

FIGS. 5D-5E are schematic sectional views of respective polishingplatens 500 d-e respectively formed by removing at least a portion ofthe first polymer layer 504 a (shown in phantom) using the method 200.FIGS. 5D-E illustrate that a desired shape for the polishingpad-mounting surface 508 d-e may be formed independently of the shape ofa surface 506 of the platen body 502 b disposed there beneath. In FIG.5D the polishing platen 500 d includes a platen body 502 b having asurface 506 comprising a convex shape with a radius of curvature R₂.Here, removing the portion of the first polymer layer 504 a forms acoating layer 504 d. The coating layer 504 d comprises a pad-mountingsurface 508 d having a radially symmetric convex shape such as describedin FIG. 5B. The radius of curvature R₂ may be the same, more, or lessthan the radius of curvature R₁. In FIG. 5E the polishing platenincludes the platen body 502 b and removing the portion of the firstpolymer layer 504 a forms a coating layer 504 e and a pad-mountingsurface 508 e having a radially symmetric concave shape such asdescribed in FIG. 5C.

In some embodiments, the polishing platens 500 d-e are formed bymachining the surface 506 of the platen body 502 b to have a desiredradially symmetric convex shape (as shown) or a desired radiallysymmetric concave shape (not shown) before forming the first polymerlayer 504 a there over. Machining the surface 506 of the platen body 502b to have a desired radially symmetric shape prior to the formation ofthe first polymer layer 504 a beneficially reduces the thickness of thefirst polymer layer 504 a required to form the desired concave or convexpad-mounting surface 508 d,e. For example, if a concave pad mountingsurface 508 e is desired, such as shown in FIG. 5E, the platen body 502b may be machined to have a substantially concave surface (not shown)prior to the formation of the first polymer layer 504 a. Machining thepad-mounting surface 508 d,e before forming the first polymer layer 504a there over reduces the chance of a mismatch of desired shapes betweenthe pad-mounting surface 508 e and the surface 506 of the platen body502 b, such as shown in FIG. 3E.

In FIG. 5E, the surface 506 of the platen body 502 b has surface shapethat may have resulted from deformation of the platen body 502 b duringthe relatively high temperature process used to form the first polymerlayer 504 a there over. As a result, the initial thickness t_(i) of thefirst polymer layer 504 a required to form a desired concavepad-mounting surface 508 e is greater than a thickness that would beneeded if the surface 506 of the platen body 502 b there beneath had agenerally concave shape. Thus, in embodiments where a convex or concavepad-mounting surface 508 e is desired, forming a generally radiallysymmetric convex or concave shape in the surface 506 of the platen body502 b reduces the chances of mismatched surface shapes followingformation of the first polymer layer 504 a. Reducing the chances ofmismatched surface shapes following the relatively high-temperatureformation process of the first polymer layer 504 a beneficially reducesthe required initial thickness t_(i) of the first polymer layer 504 a toachieve the desired shape of the pad-mounting surface 508 e.

FIGS. 5F-5H are schematic sectional views of respective polishingplatens 500 f-h illustrating alternate shapes of pad-mounting surfaces508 f-h that may be formed in the respective coating layers 504 f-husing the methods set forth herein. In FIGS. 5F-5H the shapes of thepad-mounting surface 508 f-h are formed by removing at least a portionof the first polymer layer 504 a (shown in FIG. 5A) using the methodsset forth herein. In other embodiments, the shapes of the pad-mountingsurfaces 508 f-h may be formed by machining the surface 506 of theplaten body 502 a to have a desired shape before forming the firstpolymer layer 504 a there over. In some embodiments, desired shapes ofthe pad-mounting surfaces 508 f-h are formed by both machining thesurface 506 and removing at least portions of the first polymer layer504 a formed thereon. In some embodiments, the profile of the surface508 f-h, as measured relative to the reference plane P, includes one ormore radially symmetric features that are desirably formed by machiningthe surface 506 and/or removing at least portions of the first polymerlayer 504 a formed thereon. As illustrated in FIGS. 5F-5H, the surfaces508 f-h may include at least one of a radially symmetric depression D(FIG. 5F) and radially symmetric peak PK (FIG. 5G) positioned betweenthe center C and the edge E of the platen 500 g. The radially symmetricdepressions and radially symmetric peaks thus form annular features thatare symmetric relative to the central axis C of the platen.

In FIG. 5F, the pad-mounting surface 508 f has a platen radius r_(p) andthe reference plane P is coplanar with the pad-mounting surface 508 f ator proximate to the radius r_(p) The center C of the pad-mountingsurface 508 f is disposed below the plane P and is spaced aparttherefrom by a distance Z₁ of about 10 μm or more, such as about 20 μmor more, about 30 μm or more, about 40 μm or more, about 50 μm or more,about 60 μm or more, or for example about 70 μm or more. In otherembodiments, the center C of the pad-mounting surface 508 f extendsabove the plane P by a distance of about 10 μm or more, such as about 20μm or more, about 30 μm or more, about 40 μm or more, about 50 μm ormore, about 60 μm or more, or for example about 70 μm or more. In otherembodiments, the center C of the pad mounting surface 508 f issubstantially coplanar with the plane P.

Here, the pad-mounting surface 508 f comprises an annular portion (atradius r₁) disposed between the center C, or a radius proximate thereto,and a radius at or proximate to the circumferential edge E of thepad-mounting surface 508 f. The annular portion is spaced apart from theplane P by a distance Z₃ which is greater than the distance Z₁, i.e.,the annular portion of the pad-mounting surface 508 f at the radius r₁is lower than both the center C of the pad-mounting surface 508 f, or afirst radius proximate to the center C, and the radius at, or proximateto, the circumferential edge E. Here, distance Z₃ is about 10 μm ormore, such as about 20 μm or more, about 30 μm or more, about 40 μm ormore, about 50 μm or more, about 60 μm or more, or for example about 70μm or more. In some embodiments, the low point of the annular portion,here at radius r₁, is disposed between about ⅓ to about ⅔ of a radialdistance from the center C to the circumferential edge E.

In some embodiments, e.g., where the pad-mounting surface 508 f isshaped by removing at least portions of a polymer layer 504 a (FIG. 5A)formed on the platen body 502 a, a thickness t₃ at the third radius isless than both the thicknesses t_(c) and t_(e). In some embodiments, adifference between the thickness t₃ and one or both of the thicknesst_(c) and the thickness t_(e) is about 10 μm or more, such as about 20μm or more, about 30 μm or more, about 40 μm or more, about 50 μm ormore, about 60 μm or more, about 70 μm or more, about 80 μm or more, orabout 90 μm or more.

Here, the center C of the pad-mounting surface 508 f is disposed belowthe plane P and is spaced apart therefrom by a distance Z₁ of about 10μm or more, such as about 20 μm or more, about 30 μm or more, about 40μm or more, about 50 μm or more, about 60 μm or more, or for exampleabout 70 μm or more. In other embodiments, the center C of thepad-mounting surface 508 f extends above the plane P by a distance ofabout 10 μm or more, such as about 20 μm or more, about 30 μm or more,about 40 μm or more, about 50 μm or more, about 60 μm or more, or forexample about 70 μm or more. In other embodiments, the center C of thepad mounting surface 508 f is substantially coplanar with the plane P.

It should be noted that the position of the reference plane P withrespect to the uppermost surfaces of the pad-mounting surfaces 508 b-hdescribed herein is not particularly limiting and description of surfaceheights as above or below the reference plane P may be modified withrespect to the definition thereof. For example, in an alternatedescription of FIG. 5F, a reference plane (not shown) may be defined ascoplanar with the pad-mounting surface 508 f at the radius r₁ and thesurface heights at the both the center C and circumferential edge E ofthe pad mounting surface 508 f would thus be above the reference plane.

In FIG. 5G, the pad-mounting surface 508 g comprises an annular portion(at third radius r₁) disposed between the center C, or a first radiusproximate thereto, and a second radius at or proximate to thecircumferential edge E of the pad-mounting surface 508 g. The annularportion is coplanar with the reference plane P. The pad mounting surface508 g at the center C, or at a first radius proximate thereto, isdisposed below the reference plane P and is spaced apart therefrom by adistance Z₁. The pad-mounting surface 508 g at a radius at, or proximateto, the circumferential edge E of the pad-mounting surface is disposedbelow the reference plane P and is spaced apart therefrom by a distanceZ₂ which may be the same or different as the distance Z₁. Thus, theannular portion of the pad-mounting surface 508 g at the third radius r₁is higher than both the center C of the pad-mounting surface 508 g, or afirst radius proximate to the center C, and the second radius at, orproximate to, the circumferential edge E. Here, distance Z₁ is about 10μm or more, such as about 20 μm or more, about 30 μm or more, about 40μm or more, about 50 μm or more, about 60 μm or more, or for exampleabout 70 μm or more. In some embodiments, the annular portion at thethird radius r₁, is disposed between about ⅓ to about ⅔ of a radialdistance from the center C to the circumferential edge E.

In some embodiments, e.g., where the pad-mounting surface 508 g isshaped by removing at least portions of a polymer layer 504 a (FIG. 5A)formed on the platen body 502 a, a thickness t₃ at the third radius ismore than both the thicknesses t_(c) and t_(e). In some embodiments, adifference between the thickness t₃ and one or both of the thicknesst_(c) and the thickness t_(e) is about 10 μm or more, such as about 20μm or more, about 30 μm or more, about 40 μm or more, about 50 μm ormore, about 60 μm or more, about 70 μm or more, about 80 μm or more, orabout 90 μm or more.

In FIG. 5H at least portions of the pad-mounting surface 508 h slopeupwardly from a first radius at the circumferential edge E to a secondradius r1 disposed at, or proximate to, the center C. The referenceplane P is parallel to a surface of the pad-mounting surface 508 h alonga radius thereof, e.g., along the radius r_(p). Here, the pad-mountingsurface 508 h has a generally conical shape when viewed in cross sectionso that a circular portion of the pad-mounting surface 508 hconcentrically disposed about the center C and having the radius r₁ iscoplanar with the reference plane P. Here, the thicknesses t_(c) andt_(e) and the distance Z₂ may be in the same ranges as in any one orcombination of the other embodiments described herein.

In some embodiments, the thicknesses of the coating layers at thedifferent radial locations from the center C of the pad-mountingsurfaces set forth herein are averaged from a plurality of thicknessmeasurements taken at a corresponding plurality of equidistant locationsalong the respective radius. For example, the thicknesses set forthherein may be averaged from 3 or more thickness measurements taken atlocations that are equidistant from one another as measured along arespective radius, such as measurements from 4 or more equidistantlocations, or from 5 or more equidistant locations.

In some embodiments, the distances Z₁, Z₂, and Z₃ of the pad-mountingsurfaces 508 b-h from the plane P at the different radial locations fromthe center C are averaged from a plurality of measurements taken at acorresponding plurality of equidistant locations along the respectiveradius. For example, the distances Z₁, Z₂, and Z₃ may be respectivelyaveraged from 3 or more measurements taken at locations that areequidistant from one another as measured along a respective radius, suchas 4 or more measurements from equidistant locations, or 5 or moremeasurements from equidistant locations.

FIG. 6 is a diagram illustrating a method of polishing a substrate usinga polishing platen formed according to embodiments described herein. Atactivity 602 the method 600 includes urging a substrate against apolishing pad in a presence of a polishing fluid. Here, the polishingpad is disposed on a polishing platen. The polishing platen may beformed according to any one or combination of the embodiments set forthherein. The polishing platen includes a cylindrical metal body having alow-adhesion-material coating layer formed thereon. Here, the coatinglayer is disposed on a surface of the metal body to form a polishingpad-mounting surface, a difference in height between a center of thepad-mounting surface and along a radius radially outward form the centeris about 25 μm or more. The coating layer may be formed to provide apad-mounting surface having any of the shapes and/or features describedabove.

Embodiments herein provide for the manufacturing of polishing platenshaving low-adhesion material surfaces with controlled and repeatableflatness profiles and/or other desired surface shapes. Beneficially, thepolishing platens herein may be formed to have convex or concave shapesthat may be used to fine-tune the polishing performance of one or moreindividual polishing systems for a particular substrate polishingprocess.

While the foregoing is directed to embodiments of the presentdisclosure, other and further embodiments of the disclosure may bedevised without departing from the basic scope thereof, and the scopethereof is determined by the claims that follow.

1. A method of manufacturing a polishing platen, comprising: positioninga polishing platen on a support of a manufacturing system comprising thesupport and a cutting tool facing there towards, wherein the polishingplaten comprises a cylindrical metal body having a polymer layerdisposed on a surface thereof, wherein the polymer layer has a thicknessof about 100 μm or more; and removing at least a portion of the polymerlayer using the cutting tool to form a pad-mounting surface.
 2. Themethod of claim 1, wherein a difference in height between the center ofthe polishing pad-mounting surface and a point disposed radially outwardtherefrom is about 25 μm or more.
 3. The method of claim 1, wherein thepolymer layer comprises a fluoropolymer.
 4. The method of claim 1,wherein a mean thickness of the polymer layer is about 100 μm or more,removing the portion of the polymer layer forms a coating layer, athickness of the coating layer varies by about 25 μm or more across adiameter of the polishing platen, and the polishing pad-mounting surfacecomprises a concave shape.
 5. The method of claim 1, wherein a meanthickness of the polymer layer is about 100 μm or more, removing theportion of the polymer layer forms a coating layer, a thickness of thecoating layer varies by about 25 μm or more across a diameter of thepolishing platen, and the polishing pad-mounting surface comprises aconvex shape.
 6. The method of claim 1, wherein a mean thickness of thepolymer layer is about 100 μm or more, removing the portion of thepolymer layer forms a coating layer, a thickness of the coating layervaries by about 25 μm or more across a diameter of the polishing platen,and a flatness across the diameter of the polishing pad-mounting surfaceis about 25 μm or less.
 7. The method of claim 1, wherein thepad-mounting surface has a first surface height at a first radius and asecond surface height at a second radius, the second radius is disposedradially inward of the first radius, the first and second surfaceheights are measured as respective distances from a reference plane thatis parallel the pad-mounting surface at the first radius, and adifference between the first and second surface heights is about 25 μmor more.
 8. The method of claim 1, wherein the pad-mounting surface hasa first surface height at a first radius and a second surface height ata second radius, the second radius is disposed radially inward of thefirst radius, the first and second surface heights are measured asrespective distances from a reference plane that is parallel thepad-mounting surface at the first radius, the pad-mounting surface has athird surface height at a third radius, the third radius is disposedbetween the first radius and the second radius, the third surface heightis coplanar with the reference plane, and the first and second surfaceheights are both disposed above the reference plain or are both disposedbelow the reference plane.
 9. A polishing platen, comprising: acylindrical metal body; and a polymer coating layer disposed on themetal body to form a circular pad-mounting surface having a firstsurface height at a first radius and a second surface height at a secondradius, wherein the second radius is disposed radially inward of thefirst radius, the first and second surface heights are measured asdistances from a reference plane that is parallel the pad-mountingsurface at the first radius, and a difference between the first andsecond surface heights is about 25 μm or more.
 10. The polishing platenof claim 9, wherein the first radius is disposed proximate to the centerof the pad-mounting surface.
 11. The polishing platen of claim 9,wherein the pad-mounting surface has a third surface height at a thirdradius, the third radius is disposed radially outward of the secondradius, the second surface height is coplanar with the reference plane,and the first and third surface heights are both disposed above thereference plain or are both disposed below the reference plane.
 12. Thepolishing platen of claim 9, wherein the polymer coating layer has afirst thickness at the first radius and a second thickness at the secondradius, and a difference between the first thickness and the secondthickness about 25 μm or more.
 13. The polishing platen of claim 9,wherein the polymer coating layer has a first thickness at the firstradius, a second thickness at the second radius, and a third thicknessat a third radius, the third radius is disposed radially outward of thesecond radius, and the second thickness is greater than both the firstand third thicknesses.
 14. The polishing platen of claim 9, wherein thepolymer coating layer comprises a fluoropolymer.
 15. A polishing platen,comprising: a cylindrical metal body; and a polymer coating layerdisposed on the metal body to form a pad-mounting surface, wherein athickness of the polymer coating layer changes from a first radius ofthe pad-mounting surface to a second radius disposed radially inwardfrom the first radius, and a difference between the thickness at thefirst radius and the second radius is about 25 μm or more.
 16. Thepolishing platen of claim 15, wherein the thickness at the first radiusis averaged from a plurality of thickness measurements taken at acorresponding plurality of equidistant locations along the first radiusand the thickness at the second radius is averaged from a plurality ofthickness measurements taken at a corresponding plurality of equidistantlocations along the second radius.
 17. The polishing platen of claim 15,wherein the thickness of the polishing coating layer changes from thefirst radius to a third radius, wherein the third radius is disposedbetween the first radius and the second radius, and the third thicknessis greater than both the first and second thicknesses.
 18. The polishingplaten of claim 15, wherein the thickness of the polishing coating layerchanges from the first radius to a third radius, the third radius isdisposed between the first radius and the second radius, and the thirdthickness is greater than both the first and second thicknesses.
 19. Thepolishing platen of claim 15, wherein the pad-mounting surface has afirst surface height at the first radius and a second surface height atthe second radius, the first and second surface heights are measured asdistances from a reference plane that is parallel the pad-mountingsurface at the first radius, and a difference between the first andsecond surface heights is about 25 μm or more.
 20. The polishing platenof claim 15, wherein the polymer coating layer comprises afluoropolymer.